Coded railway signaling system



A. L. JEROME 2,389,982 GODED RAILWAY szemuuq SYSTEM F iled March 2, 19447 Sheets-Sheet 1 Eeofzfip I Unif.

43W fig 114.

v INVENTOR 9 Ari/ ap fer'ome Hff ATTORNE Y Nov. 27,1945. A. JEROME2,339,932 I CODED RAILWAY SIGNALING SYSTEM Fiied March 2, 1944 7Sheets-Sheet 2 1 IgWIH 45' 59 l I l I v 55W 0 fig. 5.

INVENTOR Ari/2a! Z Jepame;

I Q a M HI! ATTORNEY Nov.

A. L. JEROME 2,389,982

CODED RAILWAY SIGNALING SYSTEM WWW iled March 2, 1944 7 Sheet-Sheet a 61 5W5 amp f I 5 (I I 1095 1;! L L 77 a @X J 79 1;; 6X Q .7. Turned LaAlzePnafon Q'ZMIQJL HIT ATTORNEY Nov. 27, 1945. A. L. JEROME 2,389,982

CODED RAILWAY SIGNALING sxsmm Filed March 2, 1944 7 Sheets-Sheet 4 (X'169 wx" HIT ATTORNEY W A. l... JEROME CQDED RAILWAY SIGNALING SYSTEM '7Sheets-Sheet 5 Filed March 2, 1944 INVENTOR BY Ami 2UP Z k/kpome a f H13ATTORNEY NEW. I A, L JEROME CODED RA ILWAY SIGNALING SYSTEM Filed March2, 194 7 Sheets-Sheet 7' INVENTOR Alffillf' Z. Jepame @if N H11!ATTORNEY the section rails,

, Patented Nov. 27, 1945 CODED RAILWAY SIGNALING SYSTEDI Arthur L.Jerome, Edgewood, Pa., assignor to The Union Switch & Signal Company,Swissvale, Pa., a corporation of Pennsylvania Application March 2, 1944,Serial Nol' 524,708

11 Claims.

. My invention relates to coded railway traffic controlling apparatus.

In application for Letters Patent of the United States, Serial No.412,279 of James J. Van Horn,

' now Patent No. 2,344,333, granted March 14, 1944,

there is shown a signaling system for use'on stretches of single trackover which traflic may move in either direction. In the system of theVan Horn application'each track section is provided with two trackcircuits, one for each direction of trafllc, while the system operatesso that when trafllc is established for either direction coded energy issupplied to the rails of each track section at the. exit end thereof andoperates the track circuit apparatus for that direction of traiflc tocontrol the wayside signals. The system of the Van Horn application isalso arranged so that on movement of a train through the track stretchsteady. energy may be supplied to the stretch at the entrance endthereof and operates the apparatus of the track circuits for the otherdirectionof traflic to cause the steady energy to be cascaded throughthe stretch to the exit end of the stretch to discontinue the supply ofcoded energy to the stretch when the stretch is vacated.

In some situations, it is desirable to provide means for indicating atthe exit end of each section when that section is occupied. This meansmay'be employed for any appropriate purpose as, for example, to controlthe supply of energy to th lamps of the wayside signal for the adjaecent track section in advance, or to control the supply of codedalternating current cab signal control energy to the section rails.

It has heretofore been proposed to govern approach control means byfeed-back energy supplied to the rails of a track section in theintervals between impulses of master code supplied over It is an objectof this invention to provide. for each track circuit of a track sectionhaving two track circuits, one for each direction of traflic,

approach control facilities governed by feed-back energy.

Another object of the invention is to provide in a signalirig system ofthe type shown in the Van Horn application, approach control facilitiesoperated by feed-back energy for each direction .of trafllc in eachtrack section.

A further object of this invention isto provide a system of the typedescribed which is arrangedv so that the approach control facilities foreither direction of tramc are not operative until that direction oftramc has been established.

Another object of the invention is to provide for a track section trackcircuit apparatus of the type described which is arranged so thatneither master code nor feed-back energy employed in.

the track circuit for one direction of trailic will I interfere with thetrack circuit apparatus for the other direction of traflic.

A further object of the invention is to provide for a track sectiontrack circuit apparatus of the type described which is arranged so thatthe track circuit apparatus for either direction of traflic will not beimproperly operated by energy stored in the section rails as a result ofthe supply to the sectionrails of master code or feed-back energy to thetrack circuit for either direction of traflic. Another object of theinvention is to provide coded track circuit apparatus of the typedescribed which is arranged so that one approach control relay servesfor one track section when trailic is established for one direction andserves for the adjoining track section when trafiic is established forthe other direction of traflic.

A further object of the invention is to provide a system of the typedescribed which incorporates means for energizing the approach controlrelays when neither direction of traflic is established in, the trackstretch. Another object ofthe invention is to provide apparatus of thetype described and arranged to reduce or eliminate establishment of theapproach controlled circuits on a change in the established direction oftrafiic in the track stretch.

A further object of the invention is to provide 7 for use in .a systemof the type described front 35 and back contact coding cut-sectionapparatus." Anotherobject of the inventionv is to provide for use in asystem of the type described equipment for use at a highway crossing tocontrol the crossing signals and to also control the supply of coded cabsignal control energy to the approach sections to the highwayintersection.

' Other objects of the invention and features of novelty will beapparent from the following I description taken in connection with theaccompanying drawings.

I shall describe one form of apparatus embodying my invention togetherwith modifications thereof which I may employ, and shall then point outthe novel features thereof in claims.

-Similar. reference -.characters refer to similar parts in each of theseveral views.

In the drawings,

Figs. 1A and 1B,' when placed together with Fig. 13 at the right, form adiagram of a track 55 section and the adjacent ends of th two adioin ingtrack sections equipped with signalin'gappaf ratus embodying myinvention;

Fig. 2 is a fragmentary diagram showing means which may be employed inplace of that" shown in Fig. 1;

Fig. 3 is a diagram showing apparatus which may be employed at acut-section where back contact coding is employed;

Fig. 4 is a diagram showing apparatus which may be employed at acut-section where'iront contact coding is employed; and

Figs. 5A and 513,. when placed together with Fig. 5B at the right, forma diagram of apparatus which may be employed at a highway intersecstion.

Referring to Figs. 1A and 1B of the drawings, there is shown a stretchof railway track having track rails l and 2 which are divided byinsulated joints 3- into track sections for signaling purposes. Onecomplete track section designated ST, and portions of the adjacent endsof the adjoining track sections designated 4T and BT, are shown. Forpurposes of illustration it will be assumed that the right-hand end ofthe track stretch is east and that the left-hand end of the stretch iswest so that train movements from left to right are eastbound whiletrain movements from right to left are westbound.

The track stretch is'equipped with coded signaling apparatus of the typeshown in the above 80 identified application of James J. Van Horn, whilethe track circuits have been modified to provide for the supply offeed-back energy over the section rails to control energization ofapproach control relays which govern the supply of coded alternatingcurrent cab signal control energy to the section rails, and to alsocontrol the supply of energy to the lamps of the wayside signals.

The construction and operation of the locomotive cab signal apparatusgoverned by the coded alternating current supplied to the track rails isnot a part of this invention and this equipment may be constructed asshown-in Letters Patent of the United States No. 1,986,679, issuedJanumy 1, 1935, to Lloyd V. Lewis.

The alternating current supplied to the section rails may besuppliedfrom a commercial source and may be distributed throughout thetrack stretch by a transmission line, not shown,

.while the terminals of this source are designated BX and CX in thedrawings.

- Each signal location is provided with a source of direct current, suchas a storage battery not shown, the terminals of which are designated BandCin the drawings. I

.As explained in the Van Horn application; when the track stretch isconditioned for eastbound traflic, coded ener y is, supplied at the eastend of thetrack stretch and is cascaded through the various tracksections to the west end of the stretch to cause a signal at that pointto display a permissive indication. Similarly,

when the track stretch is conditioned for westbound traflic, codedenergy is supplied at the west end of the track stretch and is cascadedthrough thevarious track sections to the east end of the stretch tocause the signal at that point to display a permissive indication. Inaddition.

on movement of a train throughthe track stretch in either directionsteady energy may be'supplied to the stretch and is cascaded through thestretch behind the train to out ofl the supply of coded energy over therails of the-various track-sec- 76 :ase aesa xtions-and to indicate atthe exit end of the sectlon when the stretch is vacated.

The equipment is shown in Figs. 1A and 1B in the condition which itassumes when the stretch is vacant and is conditioned for eastboundtrafflc.

' At this time, energy of code frequency issupplied to the rails ofsection 6T afthe righta hand orexit end thereof. As explained in connection with section 6T, this energy is supplied from a track batteryand is of such polarity that the positive terminal of the battery isconnected to the lower rail 2. This energy feeds fromtrack rail 2 overback contact if] of coding relay SWCTM, winding of track relay GETR fromleft to right, back contact ii of relay GEIR, track winding l2 of relayGWFB, and back contact l4 of coding relay BECTM to track rail I. Thisenergy picks up the contact of track relay SE'R. while it moves thecontact of polar stick relay GWFB to its left-hand or normal position.

The track relays are all of the polar biased neutral type the contactsof which become picked up when and only when energy flows through therelay winding in a particular direction, while each of these relays isarranged so that its contact is picked up on flow of energy through therelay winding in the direction indicated by the arrow on the relay.

The feed-back detector relays F3 are of the polar stick type, thecontacts of which are moved to one position by energy of one polarityand are moved to their other position by energy of the other polarity,while the contacts of these relays when moved to either position remainin that position until energy of the polarity effective to move therelay contact to its other position is supplied to the relay.

The circuits for supplying energy to the rails of a section from thetrack and teed-back batteries at an end of the section are arranged sothatthe positive terminal oi. one of these batteries is connected to onetrack rail and the positive terminal of the other battery is connectedto the other track rail. Accordingly, energy of one polarity is suppliedto the section rails from one battery and energ of the other polarity issupplied to the section rails from the other battery and to identify thepolarity of the energy intended these have been designated normalandreverse polarity.-

Similarly, at each end of each section there are two track relays, oneof which responds to energy or one polarit supplied over the track 5rails; that is,. to energy supplied when the positive terminal of thesource is connected to one track rail, while the otherrelay responds toenergy of the other polarity supplied over the track rails, that is, toenergy supplied when the positive terminal oi the source is connected tothe other track rail, and to identify the polarity of the energyintendedthese have been designated normal and reverse polarity.

The terms normal and reverse polarity are purely arbitrary designationsand either track rail may be connected to the positive terminal of thesource to provide energy of normal polarity, but the batteries and trackrelaysat both ends of a section must be arranged in thecorrectrelationship to each other.

On picking up of relay BEI'R energy is supplied over its front contactll to slow releasin relay GEFSA, while on release .oi'relay OETR energyis supplied over back contact I! of relay BEIR, front contact of relayBEFSA,;and back picked up and its contact 20 establishes the circuitfor. supplying energy to the primary wind-- ing of decoding transformerCDT so that on coding operation of relay BTM energy is induced in' thetransformer secondary windings, Energy from one of these secondarywindings is rectified by a contact of relay TM, as explained in LettersPatent of the United States No. 2,237,788, issued April 8, 1941, toFrank H. Nicholson and Leslie R. Allison, and is supplied to'slowrelease relay 6H, while energy from the other secondary winding issupplied through a resonant rectifier unit ISIIDU to relay SJ. As relays6H and SJ are picked up, energy may be supplied over front contact 22 ofrelay 6H and front contact 23 of relay 1 SJ to the green lamp G ofsignal SSE, However, as hereinafter'explained, as long as section ST isvacant, relay SFBP is picked up and its contact 24 interrupts thecircuit of the lamps of signal SSE,

On continued code following operation of track rela GETR, energy issupplied to relay SEFSA each time the track relay picks up, while eachtime the track relay releases, energy is supplied to relay STM and itpicks up to supply energy to relay SBSA. The relays FSA and BSA are of atype the contacts of which are slow to release so that the contacts ofthese relays remain picked up in the periods during which the supply ofenergy to the relays is interrupted. Similarly, the relay 611 is of aype the contacts of which are slowlto release so that its contactsremain picked up in the intervals between energy impulses suppliedfrom'the decoding transformer.

On release, of the contact of the track relay GETR, energy is suppliedto relay OTM and its contacts pick up, The relay STM does not pick upinstantaneously and in-the period from re lease of track relay SETRuntil picking up of relay GTM, energy is supplied to relay BEIR overback contact ii of the track relayjETR, front contact t6 of relay SEFSA,back contact I! of relay SWFSA, asymmetric unit 52, back contact 53 ofrelay BTM, front contact 54 of relay 6H, frontcontact $6 of relay GEFSA,back contact 51 of relay BWFSA, and back contact 59 of relay BWCTM, Theenergy supplied to relay SEIR picks up its contact ll so that energy issupplied from batter SEBB to the rails of section ST. The energy fromthe battery GEBB flows from the positive terminal of the battery overfront contact llof relay SE13, through the winding of track relay GE'I'Rfrom right to left, and over back contact In of relay SWC'IM to trackrail 2, while the negative terminal of this battery is connected overback contact I l of relay'BWCTM to track rail I. The energy suppliedfrom battery UEBB flows through the winding of the track relay tE'I'R inthe wrong direction to pick up the relay contact while, as explained inconnection with section ET, the energy supplied from battery EBB to therails of section 6T feeds to the BI is connected from the energizingcircuit for relay EIR to terminal O. .The resistors 80 and BI providesnubblng circuits for the relay SEIR, and' on interruption of thecircuit of the relay, delay release of the relay contacts for a periodlong enough to insure that feed-back energ will be supplied to the railsof section 6T for a period sufficient to operate the feed-back detectorrelay, but short enough'to insure thatthe relay BEIR will release beforethe start of the next "on period in the code supplied to section GT,

On release of relay SEIR, the supply of energy from battery EBB to therails of section GT is cut off and relays BETR and GWFB are connected inseries across the rails of section 6T. Because of the inductance of'thetrack-circuit of section 6T,-.on interruption of the circuit of thebattery GEBB energy may continue to flow in the track circuit in thesame direction as it was flowing when energy was supplied from thebattery to the track circuit. If this energy continues to flow aftercontact ll becomes released, energy GWFB from right to left back contactI l of relay BEIR, winding of relay SETR, and back contact ID of relayGWCTM to rail 2. This energy is ineffective to pick up the contact ofrelay GETR,

while it may move the contact of relay SWFB to its right-hand or reverseposition, but this is not objectionable sincethe circuit controlled bythe contact of relay GWFB is open at front contact 63 of relay GWS. Thearrangement of the track circuit is such that neither the supply offeedback energy to the section rails nor energy stored in the trackcircuit as a result of the'sup'ply of feed-back energy thereto willinterfere with the proper operation of the track circuit apparatus.

If contact ll of relay BEIR should engage its front and back contactssimultaneously, the battery GEBB will be connected to the track windingeast end of the section and operates thefeedthewindingoftherelay6m,whilearesistor I2 of relay GWFB and itscontact will be moved to its normal or open position, while any energysupplied to relay GETR will flow through the relay winding in the wrongdirection to pick up the relay contact. Accordingly, overlappingcontacts on relay GEIR cannot create a hazardous condition.

As relayBBSA is picked up, its contact 26 establishes acircuit for thecode transmitter ISUCT and it operates to provide coded energy of codefrequency. Energy of "75 code frequency is supplied by a continuouslyoperating code transmitter 1501'.

At this time,'energy is supplied to the directional stick relay BES overthecircuit which includes front contact 21 of relay 6H, back contact 28of relay SWFSA, and front contact 29 of relay BEFSA, so the contacts of.relay BES are picked up and its contact 30 interrupts the circuit ofrelay GWCTM and its contacts remain released to connect track relay BETRacross the rails of section 6T.

The directional stick relay BWS is released at this time and energy of180 code-frequency is supplied to coding relay SECTM over back contact32 of relay SWFSA, a contact of code transmitter I8IICT, front contact33 of relay 6H, and back contact 34 of relay BWS, and the relay SECTMoperates at the 180 code speed. 0n pick ing up of the relay SECTM, itscontacts 36 and 3] connect the track battery SETB and the secondarywinding of track transformer EETT in series across the rails of section5T with the positive terminal of the battery connected to track thetrack relay WTR but,

rail 2. The energy from the track battery BETB feeds over the rails ofsection 51 and over back contacts 39 and 40 of relay SWCTM and picks upthe contact of the track relay 5ETR, while this energy also feeds overback contact 42 of relay SEIR and through the track winding 43 of relaySWFB so that the contact of this relay is moved to its left-hand ornormal position.

In addition, on picking up of relay 5ECTM, its contact 45 establishes acircuit to energizethe local winding 46 of relay SEFB' and the relay5WIR in series so that the contact 48 of relaytistor is of relativelyhigh resistance so that it .delays release of the contact of relay 5WIRfor a very short period on interruption of the circuit of the relaywinding.

When relay SWIR, picks p, its contact 48 connects the feed-back batt r;SWBB in series with as the contacts of relay e ergy flows in this cir-On release of relay SECTM its 5ECTM are picked up, no cult at this time.

contact 45 interrupts the'circuit for energizing relays 5WIR and 5EFB inseries and thecontact 49 of relay SEFB remains in its reverse position,

while the contact 48 of relay SWIR remains picked up for a short periodbecause of the snubbing action of resistor 50 onthe relay winding. Whencontacts 36 and 31 of relay 5ECTM engage their back contacts, thebattery SWBB is connected across the section rails in series with thewindin of relay 5WTR, while the direction of flow of energy from thebattery 5WBB through the track relay is such as to hold the relaycontact released. The supply of energy from battery SWBB to relay 5WTRis cu off on release of 'relay SWIR which occurs very soon after releaseof the contacts of relay SECTM.

As previously explained, when relay BECTM is picked up, the trackbattery SETB is connected across the section rails with the positiveterminal of the battery connected to rail 2. When relay 5ECTM releases,the supply of energy from the battery SE'I'B to the section rails isinterrupted,

and because of the inductance of the track circuit energy may continueto flow therein in the same direction that it had been flowing. Whencontacts 36 and 31-01 relay 5ECTM engage their back contacts, inductiveenergy'from the track circuit tends to flow from rail 2 through theballast, and through the wheels and axles of a train if the section isoccupied, to rail I, thence overback yintact 31 of relay 5ECTM, throughwinding of elay SWTR, from right to left, front contact 48 of relay5WIR, battery 5WBB, and back; contact 36 of relay SECTM to rail 2. Thisenergy flows through the winding of the track relay SWTR in the properdirection to pick up the relay contact, but at this time energy frombattery SWBB flows through the winding of relay SWTR, in the Op ositedirection and prevents picking up of the relay contact. 1 l

Inductive energy from the track circuit, when 1 present at all, persistsfor only a very short .period 1 after interruption of the circuit of thetrack battery. The desired protection against operation of relay SWTR bythis energy is obtained if relay SWIR remains picked up and maintainsthe supply of energy from battery SWBB through the winding of relay BWTRuntil the inductive discharge from the track circuit terminates, and theresistor is of such value as'to delay release of relay 5WI R for aperiod slightly greater than that required for inductiveenergy from thetrack circuit to be dissipated.

The arrangement of the track circuit apparatus is such, therefore, thatenergy stored in the track circuit as a result of supply of energythereto from the track battery EETB when the stretch is conditioned foreastbound traffic will not cause improper operation of the track relay5WTR for the track circuit which is employed when the stretch isconditioned for westbound traflic,

The coded energy supplied from battery SE'I'B to the rails of section 5Tas a result of coding operation of relay EECTM feeds to relay SETR. andoperates it so that relays BEFSA, SBSA, 6E8, 5H and SJ are picked up,while on each movement of the contact of track relay SETR. to itsreleased position energy is supplied to relay SEIR during the pick-uptime of relay 5TM as explained in connection with relay BEIR.Accordingly, during each off period in the master code supplied tosection ET, the relay SEIR picks up and energy is supplied from thebattery 5EBB to the rails of section ET. This ener y flows from thepositive terminal of the battery over front contact 42 of relay SEIR,winding of relay BETR from right to left, back contact 40 of relaySWCTM, track rail 2, back contact 36 of relay SECTM, track winding ofrelay SEFB from left to right, back contact 48 of relay SWIR,- windingof relay SWC'IM to the'negative terminal of the battery. The energysupplied from battery 5EBB to relay 5EF'B moves the contact 49 of therelay to its left-hand or normal position so that energy is supplied-torelay 6FBP over the circuit which includes contact49, front contact 66of relay BBB, and back contact 63 of relay 6W8. During the picked-upperiods of the relay EECTM, energy is supplied to the local winding 46of relay SEFB. as previously explained, and contact 49 is moved to itsright-hand or reverse position in which, it interrupts the circuit ofrelay 6FBP. The relay BFBP is of a type the contacts of which are slowto release so the relay contacts remain picked up in the periods duringwhich the supply of energy to the relay is cut off. Accordingly, contact24 of relay BFBP interrupts the circuit of the lamps of signal SSE,while contact 68 short-circuits the primary winding of track transformerSETT over the circuit which is traced from terminal CX over frontcontact 69 of relays [ES and transformer primary winding to terminal CX.As a result alternating current is not supplied to the rails of section5T at this time, while short-circuiting of the track transformer primarywinding reduces arcing at the contacts of relay SEC'I'M.

At this time, energy of code frequency is supplied to relay 4ECTM over acircuit corresponding to that traced for relay SECTM so that energy of180 code frequency is supplied to the rails of section 4T, while theequipment for section 4T operates in the same manner as that for section5T with the result that coded energy is supplied to the adjacent sectionin the rear andstretch.

aaeaaea tilled above, coded energy is cascaded through the other tracksections to the entrance end of the track stretch to cause the eastboundsignal at that point to display a proceed indication and,

authorize an eastbound train 'toenter the track When an eastbound trainenters the track stretch, the rails of the-section at the entrance endof the stretch are shunted and the signal at the entrance to the trackstretch is caused to display its stop indication, while the equipment atthat point may operate to supply steady energy to the west end of thestretch.

When thetrain advances into section IT, the supply of feed-back energyover the section rails is cut off and the contact 10 of relay lEF'B isnot moved-to its normal position to establish the circuit of relay SFBPand the contacts of relay SFBP release so that .energy is supplied overits back contact ll, front contact I2 of relay BES, front contact 13 ofrelay H, and front contact 14 of relay U to the green lamp G of signalSSE. As relay 5W8 is released, its contact 18 interrupts the circuit ofthe lamps of signal 48W and .they remain dark. Also on release of relaySFBP its contact II interrupts the circuit short-circuiting the primarywinding of track transformer lETT, while energy is supplied to thiswinding over the circuit'which is traced from terminal BX of the sourceof alternating current over back contact ll of relay EFBP, front contact19 of relay BES, and primary winding oftransformer AETT to terminal CXof the source ofalternating current. Accordingly, on continued operationof the coding relay-IECTM, coded alternating current is supplied toftherails of section T to operate the cab signal apparatus on the locomotivepresent inthat section.

to the track transformer SETT.

When section ET. is occupied, the track relay SETR remains released andits contact 80 does not establish the circuit of relay SEFSA so itscontacts release with the result that contact 8| interrupts the circuitof relay STM and its contacts remain released and relays 5H, BJ and BBSArelease. on release'of relay 5H, its con'' tact I9 interrupts thecircuit 'of thegreen lamp G and establishes the circuit of the red lampR of signal SSE.

,relay BEs over its stick circuit which includes its own front contact95 and back contact 96 of relay GEFSA so the contacts of relay 6ESremain picked up. In addition, at this time, relays SBSA, GTM, 6H and OJrelease, while energy of 75 codefrequency is supplied to relay 5ECTMover the circuit which includes back contact 32 of relay SWFSA, acontact of the code transmitter 150T, front contact 99 of relay 6E5,back contact-33 of relay 6H, and back contact. 34 of relay 6W8. Therelay SECTM, therefore, operates to supply energy of '75 code frequencyto the rails of section 5T.

1 the adjacent section in advance and to cause alternating current cabsignal control energy to be supplied to the rails of section 6T.

As explained in the Van Horn application identified above, if theequipment at the entrance end of the track stretch is operated to permita second or following eastbound train to enter the track stretch, steadyenergy is not supplied to the track rails at the west .end of thestretch and coded energy continues to operate the track circuitapparatus. If, when the train under consideration vacates section 4T,steady energy is not supplied to the entrance end of. the track 40stretch, the energy of 75 code frequency sup- On release of relaybEFSAits contact 83 interrupts the pick-up circuit for relay 5E8, while thestick circuit is established for relay SES and 111-:

' eludes back contact 84 of relay SEESA and front contact 85 of relay5E8. The relay 5E8 is of a type the contacts of which are slow torelease so contact 85 maintains the relay stick circuit during movementof the contacts of relay BES between their picked-up and releasedpositions.

The energy supplied to relay 5E8 over its stick circuit keeps the relaycontacts picked up so that contact 88 of relay IE8 continues tointerrupt the circuit of relay SWCTM and contact 90 establishes thecircuit including. back contact 91 plied to the rails of the section as.a result of operation of relay 4ECTM will operate the equipment at theentrance end of the section to cause the signal, not shown, at theentrance end of section 4T to display its yellow or caution indication,while energy of, code frequenc is supplied to the adjacent section intheirear; The equipment for section 4T operates at .this time in themanner explained below in connection with section 6T. c

When section ET is vacated, assuming that steady energy is not suppliedat the west end of the stretch, the energy of 75 code frequency sup!plied to the section rails at the east end of the section feeds to thetrackrelay 5ETR and operates it so that relay BEFSA picks up toreestablish thecircuit of. relay 5TM, while relay ETM operates so thatrelays 533A and; 5H pick up and relay 5J remains released. On picking upof relay SEFSA, its contact 84 interrupts the stick circuit for therelay 5E8, while on picking up of relay 5H energy is supplied to relaySES over front contact I99 of relay 5H, back contact I02 of relay WFSA,and front contact 83 of relay 'SEFSA. The relay 5ES is slow enough inreleasof relay lWFSA, a contact of code transmitter 7 lamps of signalSSE.

-in'gup of relay BEFSA to picking up of-relay 5H.

-A.s relays 5E5 and 5H are picked up, energy may be supplied over frontcontact 1.2 of relay 5E8, front contact 13 of relay' 5H, and backcontact .14 of relay SJ to the yellow lamp Y of si nal SSE,

but if section .lT is vacant, relay BFBP will be picked up to preventsupply of energ to the At this time, energy, of 180 code frequency issupplied to relay EECTM over the circuit which includes back contact 9|of relay 4WFSA, a contact of code transmitter I80CT, front contact 93 ofrelay, 5H, and back contact 94 of relay 5WS, while the code transmitterI80CT is operated by energy supplied over front contact 81 of relaySBSA.

When relays SEFSA and 5H pick up, the circuit for supplying impulses ofenergy to relay SEIR on release of the contact of relay SETR is completeand the relay SEIR operates to supply impulses of feed-back energy frombattery SEBB to the rails of section 5T during the off periods in themaster code supplied to the section rails. This feed-back energyoperates the relay SEFB so that its contact 49 establishes the circuitof relay BFBP and it picks up so that contact 24 interrupts the circuitof the lamps of signal SSE and contact 68 cuts off the supply of energyto the primary winding of transformer SETT and short-circuits thiswinding.

It will be seen that when the stretch is controlled to permit followingtrainmovements, this track circuit apparatus operates to provideappropriate signal indications for the second train and to preventlighting of the signals and the supply of coded alternating current tothe rail of a track section until the section is occupied.

If it is not intended to permit a second train to enter the stretch,steady energy is supplied to the stretch at the entrance end thereof andis cascaded through the various sections in the manner about to bedescribed and cuts off transmission.

of coded energy through the track stretch.

When section M is vacated, steady energy supplied to the section railsat the west or entrance end thereof feeds to relay flWTR during areleased period of the contacts of relay 4ECIM so contact 92 of relaylWTR picks up and establishes the circuit of relay lWFSA so its contactspick up with the result that contact 9| interrupts the circuit tracedabove for supplying energy of 75 code frequency to relay fiECTM and thecontacts of relay iECTM remain released and maintain the circuit ofrelay 4W'I'R.

As long as section 5'1 is occupied, relay ms is maintained picked up byenergy supplied over its stick circuitvwhich includes back contact 84 ofrelayBEFSA and front contact 85 of relay 5E5. As long as relay 5E8is'picked up, its contact 88 interrupts the circuit of relay EWCTM andits contacts remain released with the result that track relay BETR, isconnected across the rails of section ET, while energy i not suppliedfrom track battery BWTB to the section rails.

- When section ST is vacated, codedenergy supplied from battery SETB tothe section rails as a result of coding operation of relay EECTM feeds abrief time interval the contacts of relay 5E8 release so that contact 85of relay 5ES- additionally interrupts the relay stick circuit,

5H, and back contact 84 of relay 5W8. Accordingly,- the contacts ofrelay lECI'M pick up and interrupt the circuit of relay 4WTR and itscontact releases, but as relays 4WFSA and SEFSA are both picked up nocircuit is established on release of relay 4WTR. 4

In addition, on release of relay 5ES energy is supplied to relay SWCTMover the circuit which includes front contact 9| of relay 4WFSA, backcontact I05 of :relay 5W3, back contact I08 of relay 5H, and backcontact 88 of relay 5E8. The contacts of relay SWCTM therefore pick upto connect the battery ,SWTB across the rails of section ST, and tointerrupt the circuit of relay SETR so that its contact 80 thereafterremains released.

The energy supplied from battery BWTB to the rails of section 5T feedsto track relay 5WTR during a released period of the contact of relaySECTM and picks up contact I08 of relay 5W'I'R to establish the circuitof relay SWFSA. Accordingly, the contacts of relay EWFSA pick up so thatits contact 32 interrupts the circuit for supply- 7 ing energy to relaySECTM and the contacts of relay EECTM thereafter remain released tomaintain the circuit of the relay BWTR and to discontinue the supply ofenergy from battery 5E'TB to the rails of section 5T with the resultthat even if the contact of relay EWC'I'M release to connect relay SETR.across the rails of section 5T, the contact 80 of relay '5E'I'R, willremain released and will not establishthe circuit of relay SEFSA.

As pointed out above, on release of relay 4WT'R,

' the circuit of relay 4WFSA is interrupted, and on On release of relaySES at'this time, energy is supplied to relay ECTM over the circuitwhich includes front contact of relay SEFSA, back contact 98 of relayliES, back contact 93 of relay release of relay 5ETR the circuit ofrelay SEFSA is interrupted, and these relays release after ex pirationof their release periods.

When relay AWFSA releases, its contact 9| interrupts the circuit tracedabove for supplying energy to relay SWCTM and its contacts release tocut off 'the supply of energy from battery SW'I'B to the rails ofsection ST and to connect the track relay 5ETR across the rails ofsection 5T. HowlECTM release and connect relay 4WTR across the rails ofsection 4T so that steady energy supplied to the section rails at thewest end of the section feeds to relay lWTR and picks up its contact 9?to establish the circuit of relay GWFSA and cause its contacts to pickup if they have become released, or to remain picked up if they have notbecome released.

' On picking up of the contacts of rela AWFSA,

energy is supplied to, relay 5WC'I'M over front contact 9| of relay4WFSA, back contact N5 of relay 5W8, back contact I86 of relay 5H, andback contact 88 of relay BES, and the contacts of relay 5WCTM pick up tointerrupt the circuit of relay 5ETR. and connect the battery EWTB acrossthe section rails. As the'circuit of relay SETR is. in-- terrupted, itscontact-8i remains released and does not establish the circuit of'relaySEFSA so the contacts of relay BEFSA remain released.

As relay SWCTM is now steadily energized. the battery SWTB is steadilyconnected across the rails of section ET and steady energy is suppliedover the rails of section ST. so that when section 9'! is vacated, theequipment at theeast end of section '1' operates in the manner justexplained to cause steady energy to be supplied to the rails of section9T,

As previously explained, as long as relay E8 is picked up, relay SFBP isconnected over back contact I08 of relay 5WS'and front contact I09 ofrelay 5E8 to a circuit controlled by contact I0 of relay 4EFB, and to acircuit controlled by contact IIO of relay 4WFSA. As long as section 4Tis vacant, the relay IEFB is operated by feedback energy, supplied overthe section rails and and its contacts release to establish the circuitsto energy to relay 5WCTM and establishes the circuit including backcontact 84 of relay SEFSA and back contact 98 of relay 5ES for supplyingenergy of 180 code frequency to the relay SWCTM;

Accordingly, relay 5WCTM operates to supply energy of 180 code frequencyto the rails of section 51 and relay EWTR follows code with the resultthat relay BTM repeats the track relay and relays 6H and SJ pick up.When relay 6H picks .up, energy is supplied to relay GWS over frontcontact 21 of relay 6H, back contact 29of relay GEFSA, and front contact28 of relay 5WFSA light the lamps of signal, SSE and tosupply 7 energyto track transformer 4ETT.

When section 4T is vacated, if th'estretch continues to be conditionedfor eastbound traflic, feed-back energy will again be supplied over thesection railsto operate rela 4EFB and cause it to establish thecircuitbf r lay 5FBP so that its contacts pick up to dis tinue thesupply of energy to transformer 4E and to the lamps of signal SSE.

If, at the time section 4T is vacated,steady energy is supplied to thewest end of the stretch and is repeated to section 4T, the relay 4WTRwill be operated by this energy and will establish the circuit of relay4WFSA as explained above. When relay 4WFSA picks up, its contact IIOestablishes a circuit including front contact I09 of relay5ES forsupplying energy to relay 5F'BP and its contacts pick up.

When section 5T is vacated and relay 5ES releases, as explained above,its contact I09 interrupts thecircuit of relay SFBP and this relayreleases. On release of relay 5E8, its contact I9 interrupts the circuitof transformer4ETT and short-circuits the transformer primary winding,while contact I2 of relay 5E8 interrupts the circuit of the lamps ofsignal 58E so that release of relay SFBP is without effect". The relayBFBP operates ina similar manner when section ST is vacated. I If it isnow desired to prepare the track stretch for westbound traffic, thesteady energy supplied and the contacts'of relayBWS pick up. When relay6H picks up, the supply of steady energy to relay BWC'I'M is cut off andenergy of 180 code frequency is supplied to this relay so that energy of180 code frequency is supplied to the rails of section 6T. At this time,the code transmitter I80CT is operated by energy supplied over from backcontact II5 of relay 5TM, front contact H0 of relay 5H, front contact II8 ofrelaylIWFSA, back contact II9 of relay 5EFSA, and back contact I20of relay 4ECTM. Accordingly, contact I22 of relayAWIR picks up so thatan impulse of fee 4WBB through the winding of track relay 4W'IR to therails of section 4T. The resistor I24 connected across the terminals ofthe winding of at the west end of the stretch is cut off and codedenergy is substituted therefor so that cascading of V steady energythrough the track stretch is disconrelay IWTR follows code so thatenergy is. supplied to relay 4WFSA during the picked-up periods of trackrelay contact 92, while during the released periods of contact 92,energy is supplied over back contactt92, front contact II2 of relay4WFSA, and back contact 8| of relay SEFSA to relay 5TM. Accordingly, thecontacts of relay 5'I'M pick up so that energy is supplied to relay EBSAandits contacts pick up to establish the circuit of the code transmitter3001' and to also establish the circuit of the primary winding oftransformer 5D'I' so that on continued coding operation of relay 5TM therelays 5H and SJ pick up; f v

When relay 5H picks up, energy is supplied over front contact I00 ofrelay 5H, back contact relay 4WIR, and the resistor I25 connected to thecircuit for supplying energ to relay 4WIR, delay release of relay 4WIR.so that the impulse of feedback energy supplied to,the rails of section4T is of appropriate length. I

In like manner when relay 6H picks up, energy is supplied to relay 5WIRover the circuit which includes back contact I08 of relay 5WTR, frontcontact H of relay 5WFSA, back contact I6 of relay EEFSA, asymmetricunit 52, back contact 53 of relay BTM, front contact 54 of relay 5H,front contact 51 of relay SWFSA, back contact 56 of relay GEFSA, andback contact 45 of relay 5ECTM.- Accordingly, contact 48 of relay 5WIRpicks up so that an impulse of energy is supplied from battery 5WBBthrough track 'relay 5WTR toe the rails of section 5T, while theresistor 50 connected across the terminals'of relay 5WIR and theresistor 6| associated with the circuit of relay SWIR delay release ofthe relaysothat the feed-back impulses are of proper duration.

The energy supplied from battery 5WBB to the rails of section 5T feedsto relay 5WFB over the circuit which is traced from the positiveterminal,

of battery SWBB over front, contact 48 of relay 5WIR, winding of relay5WTR from left to right, back contact 31 of relay 5ECTM, track rail I,

back contact 39 of relay 5WCTM, track winding back energy is suppliedfrom battery relay SEC'I'M to the negative terminal of the battery BWBB.

-- The energy supplied from battery ISWBB to" the relay WFB flowsthrough the winding 43 of the relay in the direction to move contact I26to its right-hand or reverse position in which it establishes thecircuit for supplying energy to relay SFBP, while during each picked-upperiod of the contacts of relay SWCTM the local wind= ing I21 of relaySWFB is energized in series with flows through the windings of trackrelays SWTR and BETR, but this energy iloyvs through the windings ofthese relays in the wrong direction to pick up the relay contacts, andoperates instead to hold the relay contacts released so there is nodanger that the feed-back energy will improperly operate the track relayof either track circuit for section' 5T; 1

Because of the inductance of the track circuit, when the relay 5WIRreleases and interrupts the circuit of battery SWBB, energy may continueto flow in the track circuit. However, this energy flows in the samedirection as the energy supplied from thebattery and this energy willflow through the winding of track relay EWTR in the wrong direction topick up the relay contact. The inductive energy from the track circuitwill flow through the track winding 65 of relay EEFB in the direction tomove contact 49 to its left-hand or normal position, but this movementof contact 49, if it occurs, is without efiect as the ircuit controlledby this contact is open at cont ct 66 of relay 8E8. I

Similarly when relay BWCTM releases and interrupts the circuit ofbattery SWTB, energy may continue to fiow in the track rails because ofthe inductance of the track circuit, and when the contacts 39 and 40 ofrelay EWCTM engage their ba contacts,1 energy from the track circuitwill end to flow to track relay BETH and to flow through this windingfrom left to right, that is, in the direction to pick up the relaycontact; However, when the contacts of relay SWCTM are picked up energyis supplied to relay EEIR and its contact 42 is picked up to connectbattery SEBB in series with'the winding of relay SETR with the positiveterminal of the battery connected to the right-hand terminal of therelay windi g. Accordingly, when the relay SWCTM releases and connectsthe track rails with 'the winding of relay EETR energy from the batterySEBB flows through the winding of the track relay SETR and preventspicking up of the contact of the track relay by inductiveenergy from thetrack circuit. At this time, relay SEIR is snubbed only by resistor I30the section rails in series with the track relay SETR so that the relayISWFB will respond to feed-back energy supplied over the section rails.

ergy from the track circuit occurring on interruption of the circuit ofeither'the track or the feed-back battery will not cause operation orthe apparatus of the track circuit for either direction It will be seenthat-when relay 5H picks/ up,

\ the supply of steady energy to relay BWCTM is cut oil and codedenergyis supplied thereto so that coded energy is supplied to the rails ofsection ST and operates relay IiWTR so that relay 6I-I picks up. As soonas relay 61:1 picks up, the circuit for supplying energy to relay EWIRis complete and it operates to supply feed-back energy to the rails ofsection ST and thus to relay EW'FB so that contact I26 oi relay SWFB ismoved. to its right-hand or reverse position in which it establishes thecircuit for supplying energy to relay SFBP.

When relay 5H picks up, its contact I00 establishes the pick-up circuitof relay 5W8 and its I of relay 5ES and front contact I08 of relay BWSto the circuit controlled by contact I26 of relay 5WFB so that onmovement of the contact I26 of relay SWFB to its reverse position byfeedback energy, energy is supplied to relay SFBP to pick up itscontacts and maintain them tact iSi interrupts one circuitshort-circuitin picked up. v

In addition, when relay 5W8 picks up, its conlamps of signal 38W.

on release oi. relay SWCTM the relay BEIR. re-

- picked up for only a very limited interval, after which it releasesand connects relay IWFB across When relay 5W8 picks up, its contact 84interrupts the circuit oi. relay IEC'I'M to insure that its contactswill remain releasedand maintain the circuit of the track relay lWTR,while contact actor relay rws establishes the circuit 101- supplyingenergy of code frequency to'relay SWCTM on occupancy of section T andrelease of relay 5H.

The equipment at the east end or section 3T operates in substantiallythe same manner at this time. When relay 8H picks up, energy is suppliedto relay 6W5 and its contacts pick up to place relay GFBP under thecontrol of contact I33 of relay SWFB, and to place transformer 6W'I'1and the lamps of signal IBW underthe control of relay BFBP.

As pointed out above, when relay IH picks up. coded energy is suppliedto relay BWC'IM and it' operates to supply coded energy to the-rails ofsection 51'' so that relayjW'I'Roperates to pick up relay 6H and therebycause relay IWIR to operate to supply iced-back energy to the rails SWSpicks up, energy will be supplied to transformer 5WT1 and to the lampsof signal SW until relay BFBP pick up. The period required a for pickingup of relay BFBP after picking up of relay SWS may be reduced to aminimum by making the relay IWS slow to pick up so that relay 5WS willnot pick up until after the equipment at the east end of section ST isconditioned to cause feed-back energy to be supplied to the sectionrails. This insures that when relay GWS picks up to place relay SFBPunder the control of relay SWFB, the relay SWFB will be. operated byfeed-back energy so its contact I26 will establish the circuit of relayBFBP.

The equipment for the other track sections operates in substantially thesame manner as that for section 5'! so that the supply of coded energyis cascaded through the remaining track sections to the east end of thetrack stretch to cause the headblock signal at that point to display apermissive indication and thus authorize a westbound train to enter thetrack stretch.

On movement of a westbound train through the track stretch, theequipment operates in subtil short-circuits the primary winding of tracktransformer SWT'I', while relay 5E8 is picked up so that'its contactI09A connects relay SFBP to the circuit controlled by contact "III ofrelay 4WFB and by contact N of relay QWFSA, and contact 19 of relay E8connects primary winding of track transformer 4ETT.to contact ll ofrelay SFBP. .As the stretch is assumed to be vacant, feed-back energysupplied over the rails of section 4T moves contact of relay 4WFB to itsnormal position in which it establishes the circuit of relay SFBP sothat the contacts of relay SFBP are pickedup.

Accordingly, contact '11 of relay SFBP shortcircuits the primary windingof track transformer GETT, while contact ll interrupts the circuit forsupplying energy to the lamps of the wayside signals, and contact Iinterrupts the circuit for supplying direct current to thetunedalternator.

When an eastbound train enters section 4T, the supply of feed-backenergy over the rails of section T is cut oil and contact 10 of relay4EFB no longer establishes the circuit of relay 5FBP and its contactsrelease and contact I35 establishes the circuit for supplying energy tothe tuned alternator so that it operates to supply alternating currentto the associated transformer, while contact ll of relay SFBP connectsthe primary winding of track transformer 4EI'I to the transformerassociated with the alternator with the result that coded alternating curent is supplied to the rails of section 4T. In addition, on

stantially the same manner as it does on movement of an eastbound trainthrough the track stretch, and a detailed description of the operationof the apparatusis unnecessary.

Similarly, when the stretch is being conditioned tor eastbound traffic,the equipment operates in substantially the same manner as it does whenthe stretch is being conditioned for westbound trafilc, and a detaileddescription of the operation of the equipment at such times isunnecessary. I

Modification shown in Fig. 2

As explained above, the system shown in Fig. 1 operates so that whentraillc is being established for either direction, energy is notsupplied tothe approach control relays FBP until one or,

the other of the associated directional stick relays picks up, whilewhen a directional stick relay is picked up and the relay FBP isreleased, energy is supplied to a track transformer and to the lamps ofone of the wayside signals. Accordingly, the system of Fig. 1 operatesat such times" to cause momentary lighting of the lamps of a waysidesignal and momentary supply of cab signal control energy to the trackstretch.

It maybe desired to eliminate this flashin of the wayside signals andmomentary supply of cab signal energy to the track rails, particularlywhere tuned alternators are employed to supply the alternating currentcab signal energy, and

front contact 109A of relay SES for supplying release of relay 5FBP itscontact 1| establishes the circuit for supplying energy to the lamps ofsignal ESE.

AWTR. picks up and its contact 92 establishes the circuit of relay 4WFSAso that its contacts pick up and contact H0 establishes a circuitincluding energyto relay SFBP. Accordingly, the contacts of relay SFBPpick up to cut off the supply of energy to the alternator and to thelamps of the wayside signals, while the primary winding of' tracktransformer lETT is short-circuited. Y

When section ST is vacated, relay EEFSA is picked up to interrupt thestick circuit for relay 5E8, as explained in connection with Fig. 1, andrelay SES releases so that its back contact-I093 establishes a circuitincluding back contact IIJBA of relay 5WS to energize relay EFBP and itscontacts remain picked up to interrupt the circuit of the alternator andof the lamps of the wayside signals. In-addition, on release of relay5E5 its contact I09A interrupts the circuits controlled by relays 4WFSAand QEFB for supplying energy to relay SFBP, while contact [9 of relay5E8 interrupts the circuit for supplying energy to transformer 4E'I'Iand short-circuits the primary winding of this transformer.

If the stretch is now to be prepared for west- I bound trafiic, thesupply of steady energy to the west end of the stretch is cut oil, andcoded energy is substituted therefor, while as explained in connectionwith Fig. 1 this coded energy is cascaded through the various tracksections. I

On the supply of coded energy to track relay 4WTR, energy is suppliedover its back contact 92, iront contact N2 of relay AWFSA, and back overthe section rails.

contact 8| of relay 5EFSA to'the relay STM so that it operates to pickup relay 5H and complete the circuit for supplying coded energy to therails of section 5T, and thus cause the equipment at the right-hand endof section 5T to operate to supply feed-back energy to the section railsto thereby cause contact I26 of relay 5WFB to be moved to its right-handor reverse position.

In addition, as explainedin connection with Fig. 1, when relay 5H picksup, it establishes a pick-up circuit for relay 5WS but relay 5WS is ofa'type the contacts of which are slow to pick up so' the relay does notpick up until after coded energy has been supplied to the rails ofsection 5T long enough to initiate operation of relay establishes thecircuit of relay 5FBP and keeps its contacts picked up.

As previously pointed out, energy is supplied to relay 5FBP over backcontacts of relays 5WS and 5ES until relay 5WS picks up, while relay 5WSis slow to pick up so that track circuit apparatus for section 51 isconditioned to cause feed-back energy to be supplied over the sectionrails before relay 5WS picks up. At this time,

the track circuit apparatus for section 5T is operated by energy of 180code frequency so there is little delay in the supply of feed-backenergy Accordingly, when relay 5WS picks up to interrupt the circuitincluding back contact I09B of relay 5ES for supplying energy to relay5FBP and to connect relay SFBP to the circuit controlled by contactfl26of relay 5WFB, the relay 5WFB is operated by feed-back energy andcontact I29 establishes the circuit of relay 5FBP. Furthermore, relaySFBP is of a type the contacts of which are slow to release so that ifat the time relay 5W8 picks up, contact I26 of relay 5WFB is in itsleft-hand or normal position, the contacts of relay 5FBP will remainpicked up until contact I of relay 5WFB is moved to its reverseposition. During preparation of th track stretch for westbound trafllc,therefore, relay 5FBP remains picked up and prevents suoply of'ener y tothe tuned alternator and to the-lamps of the wayside signals.

In like manner, the relay 5FBP remains picked up when t e stretch isbeing prepared for eastbound trafflc. The operat on of the equipment atsuch times is substantially the same as when i the stretch is beingprepared for westbound trafllc and a detailed explanation'of theoperation of the equipment is unnecessary.

Modification show'in in Fig. 3

- tion of traffic, while the equipment at adjoining ends of the twosections is arranged so that coded or steadyenergy supplied to one ofthese sections will be repeated to the other one of these sections. Inaddition, each of these trac sec-- tions is provided with approachcontrol facilities operated by feed-back energy togovern the 'supply ofalternating current cab signal control energy to the section rails.

Only the equipment atthe adjoining ends of the two sections is shown inFig. 3, and the equipment at the other ends of these sections may be thesame in construction and operation as that shown in Fig. 1- or 2.

The apparatus of Fig. 3 is shown in the condition which it assumes whenthe track stretch is vacant and is conditioned for eastbound trafllc. Atthis time, coded energy is supplied to the rails of section EIT at theright-hand end thereof and this energy feeds over back contacts I40.

andI4I of relay E'IWCTM, and back contact I42 of relay EIEIR and picksup the contact I48 of track relay ElETR, and moves the contact of relayEIWFB to its left-hand or normal position., I I

When relay E'IETR picks up, energy is supplied to relay E'I'EFSA overback contact I44 of relay W'IWFSA, back contact I45 of relay W'IWTR, andfront contact I46 of relay EIETR so the contacts of relay E'IEFSA arepicked up. Accordingly, during the released periods of relay E'IETR,energy is supplied over back contact I44 of relay W'IWFSA, back contactI45 of relay W'IWTR,

back contact I45 of relay E'IETR, and front contact I48 of relay E'IEFSAto relay lBSA so its contacts are picked up.

As relay lBSA is picked up, its contact I49 interrupts the circuit whichit controls for supplying energy" to relay 'IFBP, while contact I50establishes a circuit for energizing relay WlECTM in multiple with relay'IBSA during the released periods of relay EIETR. The circuit forsupplying energy to relay WIECTM includes back contact I44 of relayW'IWFSA, back contact I45 of relay W'IWTR, back contact I48 of relayEIETR,

front contact I48 of relay EIEFSA, front contact I50 of relay 'IBSA,back contact I5I of relay WIWFSA, and front contact I53 wf, relayEIEFSA. Accordingly, during each released period of the contact of relayE'IETR energy is supplied to relay WIECTM and its contacts pick up tosupply energy from battery WIETB to the rails of section WIT, whileduring the picked-up periods of the contact of relay EIETR the circuitof relay W'IEC'IM is interrupted and its contacts I release. The relayWIECTM, therefore, operates to supply to section WlT energy of the samecode frequency as that supplied to relay EIETR, but

with the on periods in the coded energy supplied to section W'IToccurring during the o periods in the code supplied to section E'IT.

On release of relay E'IERT to establish the circuit of relay WlECTM thecontacts of relay WIECTM do not pick up instantaneously and, in theperiod during which they remainreleased, energy is, supplied to relayEIEIR over the circuit which includes back contact I44 of relay WIWFSA,6 ck contact I of relay w1w'ra,

v back contact I45 of relay EIETR, front contact I48 of relay E-IEFSA,front contact I of relay 'IBSA, back contact I5I of relay WlWFSA, frontcontact I of relay E'IEFSA, back contact I54 of relay WIECI'M, backcontact I55 of relay W'IWFSA, and "back contact I56 of relay EIWCTM. Thesupply of energy torelay E'IEIR' is interrupted as soon as contact I54of relay W'IECTM picks up, but the energy supplied to relay EIEIR priortothis time picks up the relay contact, while the resistor I51 connectedacross the terminals of relay EIEIR, and the resistor assaasa Illconnected to the energizing circuit for relay -E'IEIR, delay release 01'the relay long enough to cause the impulse of teed-back energy suppliedto the 'rails of section EIT to be of adequate duration.

When the contact I42 of relay E'IEIR picks up, feed-back energy issupplied from battery EIEBB through the winding of track relay EIETR tothe rails of section -E'IT. This energy flow through the winding ofrelay E'IETR. in the wrdiig direction to pick up the contact of thisrelay, while the energy supplied from the battery E'IEBB to the rails ofsection E'IT operates the feed-back detector relay at the right-hand endof section E'IT.

When relay WIECTM picks up, its contact I60 establishes the circuit toenergize the relay contact I69 of relay *IFBP releases and establishesthe circuit including front contact I of relay EIEFSA for supplyingenergy to trans.- former W'IETT so that on continued coding op-' erationof relay W'IECTM, coded alternating cur-' rent cab signal control energyis supplied to the rails of section WIT to operate the cab signalequipment on the locomotive in that section.

W'IWIR and the lower winding 01 relayW'IEFB.

in series so the contact I62 of the relayW'IEFB is moved to itsright-hand or reverse position in which it interrupts the circuit ofrelay 'IFBP. The energy supplied to relay WIWIR picks up its contact Iso that battery WTWBB is connected' in series with .the winding of thetrack relay WlWTR. but as long as relay WIEC'I'M is picked up, no energyflows from the battery WIWBB.

On release of the relay WIEC'I'M, contact I60 interrupts the circuitot'relays WIWIR and WIEFB, and the relay WIWIR releases after a ,shorttime interval determined by the resistor I connected across theterminals of the relay winding. In the period after release of relayWIECTM and prior to release of relay WIWIR,

1 energy is supplied from battery W'IWBB through relay WIWTR to thesection rails and prevents operation of relay W'IWTR by inductive energyfrom the track circuit occurring on release of the relay WIECTM andinterruption of the circuit of the battery W'IE'I'B. The resistor I65delays release oi. relay WIWIR for only a very shortperiod, and onrelease of contact I64 of relay WIWIR the elays WIEFB and W'IW'I'R areconnected in series across the rails of section W'IT so that the impulseof feed-back eny supplied over the rails of section WIT at this timemoves the contact I62 of relay WIEFB to its left-hand or normalposition, but does not pick up the contact of relay W'IWTR.

0n movement'of contact I62 of relay W'IEFB to its left-hand position,energy is supplied to relay 'IFBP, over the circuit including contactIII of relay W'IEFB, back contact I61 of relay WIWFSA, and front contactI68 of relay E'IEFSA, so the contact I69 of relay IFBP is picked up toprevent supply of energy to transformer W'IETI' and to short-circuit theprimary winding of this transformer.

.When the train advances into section E'IT, the

; track relay E'IETR is shunted and ceases to establish the circuit ofrelay E-IEFSA and it re- .leasesto interrupt thecircuit of relay IBSAso' that its contacts release. On releaseof relay 'IBSA, its contact 9establishes a circuit to supply energy to relay 'IF'BP and its contactI88 is picked up to prevent supply of alternating current to thecircuits controlled by this contact. In addition, on release of relay'IBSA, its contact I interrupts the circuits for supplying coded energyto the coding relays and establishes a circuit over which steady energymay be supplied to one or the other of these relays. On release of relayEIEFSA, its contact I53 interrupts the circuit traced above forsupplying coded energy to coding relay W'IECTM, while contact I68 ofrelay E'IEFSA interrupts the circuit controlled by contact I62 of relayW'IEFB for supplying energy to relay 'IFBP, and contact I10 of relayEIEFSA interrupts the circuit for supplying energy to transformer WlETT-and short-circuits the transformer primary winding.

When section E'IT is occupied, the supply of feed-back energy to thesection rails is cut on and the 'equipmeht at the right-hand end of thissection operates to cause coded alternating current cab signal-controlenergy to be supplied to the section rails.

As explained in connection with Fig. 1, on movement of a train throughthe track stretch steady energy may or may not be supplied to thestretch in the rear of the train depending on During the picked-upperiods of the relay I WlECTM, the contact I62 of relay WIEFB is movedto its reverse position in which it interrupts the circuit of relay'IFBP, but the relay IFBP is slow enough in releasing to remain pickedup during -these periods. Accordingly, when the'stretch is conditionedfor eastbound it tramc, the relay IFBP is connected to the circuitcontrolled by contact I62 of relay WIEFB, while as long as section W'ITis vacant, relay WIEFB is operated by feed-back energy supplied over thesection rails and maintains relay 'IFBP energized.

whether or not another train is to be permitted to pass through thetrack stretch.

If steady energy is no'tsupplied to the west end oi the track stretch,the equipment will remain as described until section ET]? is vacated, atwhich time coded energy supplied at the right-hand end of the sectionoperates relay E'IETR so that relays ElEFSA and 'IBSA are picked up tothereby cause relay. WTECI'M to" operate as a repeater of relay E'IE'IRand to place relay -'IF'BP under the control of relay W'IEFB.

If steady energy is supplied to the west end of the stretch, it will becascaded through the various sections as they are vacated, as explainedin connection with Fig. 1. As will be understood from Fig. l, theequipment at a signal location operates in such manner that steadyenergy is not supplied to a section until the section. is vacated and animpulse of coded energy is supplied over the section rails.

When an easbound train enters section WIT,

the supply of feed-back energy over the section rails is cut oil andcontact I62 of relay WlEFB remains in its reverse position in which itinterrupts the',circuit of relay IFBP. Accordingly. the

to relays E1EF'SA, 138A and W1E'CTM. Accordingly, the contacts of relayWIECTM remain released and maintain the circuit of relay 'WIW'I'R sothat the contact of relay W1WTB, re-

mains picked up. After a short time interval,

, the contacts of relay E1EFSA release so that energy is supplied overback contact I48 of relay v E1WCTM. This insures that rela E1EIR willEIEFSA, back contact I48 of relay E1ETR, and front contact I45 of"'relayW1WTR to relay W1WFSA and its'contacts' pick up.. Relay lBSA'alsoreleases at this time so energy is supplied over'its back contact I49 torelay 1FBP,

E1WFB soon enough to make while energy is supplied over back contact 155of relay 1BSA, back contact I53 of relay ElEFSA,

and front contact I5I of relay W1WFSA to relay I E1WC'IM and itscontacts pick up to cause steady energy to be supplied to-the railsofsection E1T,

and thus cause steady energy to be repeated throughout the trackstretch.

'If the steady energy supplied to the west endof the track stretch iscut oil and coded energy substituted therefor, this coded energy will becascaded through thetrack stretch so that coded energy is supplied tothe west end of section W11.

- On the supply of coded energy to section W1T the relay W1WTR followscode, and energy is supplied to relay 1BSA during the released periodsof the contact of relay W'IW'IR, and the contacts of relay 1BSA ;pick upwith the result that, during" the released periods of relay W1WTR,energy is suppliedto coding relay E1WCTM over the circuit which includesback contact I48 of relay E1EFSA, back contact I46 of relayE1E'I'R; backcontact, I45 of relayWlWTR, front contact I44 of relay. W1WFSA, frontcontact I50 of relay J1B SA, back contact I58 of relay ElEFSA, and frontcontact I5I of I relay ,W'IWFSA. Accordingly, relay' E1WCTM operates asa back contact repeater of track relay W1WTR and causes coded energy tobesupplied to the rails of section E1T.

Inaddition, at this time, energy is supplied to relay W1WIR over the"circuit traced above for relay liflWQTM, plus the branch which includesback contact I12 of relay E1WCTM, back contact I18 of relay E1EFSA, andback contact I50 of re-' to thel rails of section W1T lay W1ECTM, so'therelay operates to,

cause impulses of feed-back energy to be supplied I during the ofi"periods in the code supplied to'that section. The circuit for energizingthe relay W1WI;R has the resistor I14 associated therewith, and thisresistor together with the resistor I55 connected' acro'ss the terminalsof relay W1WIR delays releaseof the relay enouglrt'o cause the feedebackirrlpulses suppliedto section-W1T to be of proper duration. The.resistor I14 is connected with the circuit at such a point in thecircuit that it isrisolated froni relay E1WCI'M as soon as the contactsof J relayE1WCTM ick up.. This prevents the resistor I14 from affectingthe release of relay EiWCTM with resultant supplied to the rails ofsection 1311'.

During the picked-up periods of relayE'IWCTM, its contact I55establishes the circuit to energize relay E1EIR in series with the localwinding of relay E'IWFB so-that contact I4 2 of relay E1EIR is picked upto connect battery 'EFEZBBLin series with the relay El'ETR and thusprevent operation of relay E1E'I'R by inductive energy from thetrackcircuit on release of. relay E1WCTM. On release of relay E1WCTMcontact I55 interrupts the circuit of relay ElEIR and connects the relaywindins to the wire leading to the back conthat shown in Fi 3 andassumes when the stretch tioned'for eastbound traflic. EIIETR isoperated by coded distortion of the code mama is interrupted assaosa lilong release of relay E1EIR. Accordingly, at this time, the releaseperiod of relay E1EIR is determined solely by resistor I51 which may beof such value as to delay release of relay ElEIR for only a short periodsubsequent to release of relay 20 terfere with the proper operation oftheequipment when the stretch ,is conditioned for eastbound tra-fflc.

At this time, relay 1BSA is. picked up so its contact I49 interrupts thecircuit which it controls for supplying energy to relay 1FBP, but atthis time relay 1FBP! is connected over front contact- I51 of relayW1WFSA and back contact I58 of relay E1EFSA to the circuit controlled bycontact I15 of;relay ETWFB so that on operation of re-- lay E1WFB byfeed-back energy the relay 1FBP is maintained picked up to preventsupply of alternating current to the track transformer E1WTB. g

' On movement of. a westbound train through the track stretch,'theequipment operates in substantially the same manner as it operates onmovement of an eastbound train through the track stretch and a detaileddescription of the op- 46 eration of the euuipment is unnecessary.

Modification shown in Fig. 4 In Fig. 4 there is shown cut sectionapparatus The equipment shown in Fig. 4' is similar to differs therefromin that the coding relays WCTM and ECTM are energized over frontcontacts of the track relays, while the impulse relays are energizedover front contacts of the coding relays. I The operation of theequipment shown in Fig, 4 is similar to that shown in Fig. 3. Theequip-" ment of Fig. 4 is shown in is .vacant and is condivAt. thistime, relay I energy supplied over the rails 0t section E8T and duringthe picked-up periods of the relay contact I18 energy is supplied torelay E8EFSA and to relay WBEC'I'M, while 6Q during the releasedperiods. of relay EIiETR the relay W8ECTM releases, andcnergy issupplied to relay 8135A and its contacts are picked up so that onrleaseof relay E8ETR energy is supplied to relay EBEIR over the circuitincluding from contact I8l ofrelay SBSA- back contact I82 of relayWBWFSA, front contact I83 of relay EBEFSA, front contact tact I85 ofrelay WBWFSA, and back contact I85 of relay EBWCTM. The supply ofenergy. to relay as soon as relay W8EGTM releases, (but sufilcientenergy is supplied to relay ESEIR in the period between release of relayI EBETR and release of relay WBECTM to pick up the relay E8EIR,while'thexesistors associated with relay 128E113. delay 1' lease ofitscontacts the condition which it which may be employed at cut-sectionswhere front contact coding is desired.

I84 of relay WBECTM, back conrectional-stick relays wan-anding thepicked-up period of relay EBEIR, are of adequate duration.

During the picked-up periods of relay WOECTM, its contact I 8'!establishes the circuit to energize relay WSWIR and the local winding ofrelay WBEFB so the contact [88 of relay WIEFB is moved to its reverseposition, while contact I of relay WBWIItpicks up to connect batterywawBB in series with the track relay WIW'I'R to prevent operation of therelay WSW-TR. by inductive energy from the track circuit.

\ During the released periods of the contacts of relay WlECTM, feed-backenergy supplied over the railsof section WB'I' energizes relay WBEFB andmoves its contact I88 to its normal position so that energy .issupplied-over this contact back contact Ill .of relay W8WFSA, and frontcontact I92 of relay ESEFSA to relay OFBP, and its contact is j pickedup to prevent supply of energy to The equipment of Fig. 5 is shown inthe conditlon which it assumes when the stretch is vacant and isconditioned for eastbound trailic. At this time, coded energy issupplied to the rails of section ET at the right-hand or east endthereof and feeds to track relay ETR. over the circuit which is tracedfrom track rail I, over back contact 203 .of coding relay E TM, windingof relay ETR from right to left, ack contact 204 of impulse relay'EIR,track winding 205 of relay EFB, and back contact 201 of relay ETCTM torail 2. The energy supplied to the rails of section ET is ofthe properpolarity to pick up the contacts of relay ETR, while this energy movesthe contact 209 of relay EFB to its reverse position,

When relay E'I'R picks up, its contacts 2| 2/ and 2 connect line wires200 and toth terminals-B and C of a source of current so that tracktransformer'wtE'l'r and -to short-circuit the transformer primarywinding. On movement of a train through the stretch, this apparatusoperates in a manner similar to the back contactcoding equipment shownin Fig.

3, and a detailed tracin of the circuits is unnecessary. Similarly, theequipment operates in a manner similar to that of Fig. 3 on a change inthe established direction of trafllc.

Modification shown m Fig.- 5

In track stretches equipped with signaling apparatus of this type,the-approach sections to-a 2 ghway crossing may be equipped with'tra'ckthe positive terminal B is connected to wire 200.

e energy supplied to the line wires flows from terminal B over frontcontact 2H) of relay ETR to'wire'20ll, over back contact N3 of relay WTR, winding of coding relay WTCTM from left to right, back contact 2 llof relay WIRA, line winding 2l5 0f relay WFBA from left to right, backcontact 2l8 of relay WTR, wire 2!", front contact2ll of relay WATR,front contact H8 01 relay' OTR, front contact 2l9. of relay EATR, and

to the rails of the approach sections, and one means for controlling thesupply of coded cab signal energy to the approach sections is shown inmy application for Letters Patent of the United States, Serial No.516,363, filed December 31, 1943, now Patent No. 2,357,235, issuedAugust 29,- 1944.

As shown in Fig. 5 the track stretch includes a' highway intersectionwhich is protected by crossing signals XS, while the track section whichincludes the intersection is divided into an intermediate section OTwhich includes the crossing, a westbound approach section EAT, and aneastbound approach section WAT. The remainder oi the track section iscompleted by sections The track sections-WAT, or and EAT are providedwith track circuits employing steady energy, while the sections WT andET are provided a with track circuits employing coded energy. Onlyemployed in the track stretch is.-transmitted around the approachsections by mcans'of a line circuit consisting of line wires 200 and 20!which are governed by the track relays of the sections WAT, o'rana EAT.v r 1 The crossing signals XS are governed by a relaylli which iscontrolled by the track relays or the seEt'ionsWAT, Oriana EAT, and bydimaybe arranged as shown front contact 2 of relay E'lltwtd terminal C.

The energy supplied over the line wires to coding relay WTCTM picksupits contacts so that energy is supplied from battery'WTETB over frontcontacts 22land 222 of relay WTCTM to the rails of section WT to operatethe equipment at the west end of the section. a When relay WTCTM ispicked up, its contact 226, establishes a circuit to energize relay WIRand the local winding of relay WFB in series so that contact 224.01relay WFB is moved to its left-hand or normal position in which itinterrupts the circuit of relay WFBP, while contact 228 of relay Will.is picked up tcsconnhhhattery WBB in series with the winding of relayWTR to thereby prevent operation of relay WTR. by inductive energy ,fromthe track circuit on reas explained in connectime thecontacts of relayWTCTM release to interrupt 1 the supp y of energy frombattery WTETB tothe rails of section WT, and to interrupt the circuit of relay wntsothat its contact. 228 releases to connect reIays'WTR and WFB across thesection rails. Accordingly, feedback energy supplied over the rails ofsection WT moves the contact 224' of relay WFB to itsrighthand orreverse position in which it establishes the circuit of relay WFBP tothereby cause its contact 225 tobe picked up and short-circuit the jprimary cs 1 ding of transformer W'I'I.

WTCTM, energy is supplied. through the-associated decoding transformertorelay WT? and its contact 229-.ispicked up to permit energy to besupplied to transformer. W'II on release of relay WFBP. In addition,impulses of energy are" supplied from a secondary winding-oithe decodingtransformer to impulse relay WIRA which is of a type which, responds toenergy of one nolarity only. The apparatus is arranged so that theenergy impulses supplied to relay WIRA on As a r I t of coding operationof relay

